Human respiratory syncytial virus (RSV) is an important pediatric pathogen causing acute viral respiratory disease in infants and young children. However, no licensed vaccines are currently available. Virus-like particles (VLPs) may bring new hope to producing RSV VLP vaccine with high immunogenicity and safety. Here, we constructed the recombinants of matrix protein (M) and fusion glycoprotein (F) of RSV, respectively into a replication-deficient first-generation adenoviral vector (FGAd), which were used to co-infect Vero cells to assemble RSV VLPs successfully. The resulting VLPs showed similar immunoreactivity and function to RSV virion in vitro. Moreover, Th1 polarized response, and effective mucosal virus-neutralizing antibody and CD8⁺ T-cell responses were induced by a single intranasal (i.n.) administration of RSV VLPs rather than intramuscular (i.m.) inoculation, although the comparable RSV F-specific serum IgG and long-lasting RSV-specific neutralizing antibody were detected in the mice immunized by both routes. Upon RSV challenge, VLP-immunized mice showed increased viral clearance but decreased signs of enhanced lung pathology and fewer eosinophils compared to mice immunized with formalin-inactivated RSV (FI-RSV). In addition, a single i.n. RSV VLP vaccine has the capability to induce RSV-specific long-lasting neutralizing antibody responses observable up to 15 months. Our results demonstrate that the long-term and memory immune responses in mice against RSV were induced by a single i.n. administration of RSV VLP vaccine, suggesting a successful approach of RSV VLPs as an effective and safe mucosal vaccine against RSV infection, and an applicable and qualified platform of FGAd-infected Vero cells for VLP production.

人呼吸道合胞病毒（RSV）是引起婴幼儿急性病毒性呼吸道疾病的重要儿科病原体。但是，当前没有获得许可的疫苗。病毒样颗粒（VLP）可能为生产具有高免疫原性和安全性的RSV VLP疫苗带来新的希望。在这里，我们将RSV的基质蛋白（M）和融合糖蛋白（F）的重组体分别构建为复制缺陷型第一代腺病毒载体（FGAd），用于共感染Vero细胞以成功组装RSV VLP 。所得的VLPs在体外表现出与RSV病毒颗粒相似的免疫反应性和功能。此外，Th1极化反应，有效的黏膜病毒中和抗体和CD8 ⁺T细胞反应是通过单次鼻内（in）施用RSV VLP而不是肌内（im）接种诱导的，尽管在用HCV免疫的小鼠中检测到了相当的RSV F特异性血清IgG和长效RSV特异性中和抗体。两条路线。接受RSV攻击后，与用福尔马林灭活的RSV（FI-RSV）免疫的小鼠相比，经VLP免疫的小鼠显示出更高的病毒清除率，但肺部病理学增强的迹象减少，嗜酸性粒细胞减少。此外，单一的RSV VLP疫苗具有诱导长达15个月可观察到的RSV特异性长效中和抗体反应的能力。我们的研究结果表明，一次接种RSV VLP疫苗可诱导小鼠抵抗RSV的长期和记忆性免疫反应，